Mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase promoter contains a CREB binding site that regulates cAMP action in Caco-2 cells
| Autor: | Dolors Serra, Anke Eggers, Fausto G. Hegardt, Concha Caudevilla, Guillermina Asins |
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| Jazyk: | angličtina |
| Rok vydání: | 2000 |
| Předmět: |
Hydroxymethylglutaryl-CoA Synthase
Transcriptional Activation Regulatory Sequences Nucleic Acid CREB Response Elements Biochemistry Gene Expression Regulation Enzymologic Chloramphenicol acetyltransferase Cyclic AMP Response Element-Binding Protein Cyclic AMP Animals Humans Protein kinase A Promoter Regions Genetic Molecular Biology Transcription factor Binding Sites ATP synthase biology Cell Biology Transfection Molecular biology Cyclic AMP-Dependent Protein Kinases Mitochondria Rats biology.protein Caco-2 Cells CREB1 Somatostatin Research Article Protein Binding |
| Popis: | cAMP increases transcription of the mitochondrial (mit.) gene for 3-hydroxy-3-methylglutaryl (HMG)-CoA synthase, which encodes an enzyme that has been proposed as a control site of ketogenesis. The incubation of Caco-2 cells with cAMP increased mit.HMG-CoA synthase mRNA levels 4-fold within 24 h. We have identified an active cAMP-response element (CRE) located 546 bp upstream of the mit.HMG-CoA synthase promoter that is necessary for the induction of expression by dibutyryl cAMP. Co-transfections of constructs, containing the CRE element of the mit.HMG-CoA synthase promoter fused to the gene for chloramphenicol acetyltransferase, with protein kinase A and a dominant-negative mutant of cAMP-response-element-binding protein (CREB) show that the response to cAMP is mediated by the transcription factor CREB. The CRE element confers responsiveness of protein kinase A to a heterologous promoter in transfection assays in Caco-2 cells. Gel-retardation assays revealed that the mit.HMG-CoA synthase CRE binds to recombinant CREB. The shifted band obtained with the putative mit.HMG-CoA synthase CRE sequence and nuclear proteins from Caco-2 cells competed with CRE sequences of other genes such as somatostatin and phosphoenolpyruvate carboxykinase. We conclude that the regulation of the expression of the gene for mit.HMG-CoA synthase in Caco-2 cells by cAMP is mediated by a CRE sequence in the promoter. |
| Databáze: | OpenAIRE |
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